Method of branching polyesters

Abstract

Linear polyester are branched by transesterification with resins having repeating or recurring polymer chain units of the formula: ##STR1## wherein m, n and p are each independent integers of 0 or 1; R represents hydrocarbyl; and E represents alkylene containing from 1 to 15 carbon atoms, inclusive, halogen- substituted alkylene of 1 to 15 carbon atoms, inclusive, alkylene of 1 to 15 carbon atoms, inclusive, substituted with a --COOR group where R is as previously defined, or alkylene having 1 to 15 carbon atoms substituted with a monovalent group of the formula: ##STR2## wherein X represents one of hydrogen, hydrocarbyl or ##STR3## wherein R is as defined above; provided there is at least one moiety present, containing an R group.

What is claimed is: 
     
       1. A process for branching a thermoplastic, linear, polyester resin, which comprises; providing said resin;   homogeneously mixing with the resin, a branching proportion of a thermoplastic, polymeric, branching resin having recurring polymer chain units selected from those of the formula: ##STR20##  wherein m, n and p are each independent integers of 0 or 1; R represents hydrocarbyl; and E represents alkylene containing from 1 to 15 carbon atoms, inclusive, halogen--substituted alkylene of 1 to 15 carbon atoms, inclusive, alkylene of 1 to 15 carbon atoms, inclusive, substituted with a--COOR group where R is as previously defined, or alkylene having 1 to 15 carbon atoms substituted with a monovalent group of the formula: ##STR21##  wherein X represents one of hydrogen, PG,30 hydrocarbyl or ##STR22##  wherein R is as defined above; provided there is at least one moiety present, containing an R group; and   effecting a branching transesterification reaction of the linear polyester resin with the branching resin.   
     
     
       2. The process of claim 1 wherein m is 1 and n is 0. 
     
     
       3. The process of claim 2 wherein R represents alkyl. 
     
     
       4. The process of claim 1 wherein m, n and p are each 1. 
     
     
       5. The process of claim 4 wherein E represents alkylene and R is alkyl. 
     
     
       6. The process of claim 4 wherein m and p are each 0; n is 1; E represents alkylene substituted with a--COOR group and R is alkyl. 
     
     
       7. The process of claim 1 wherein the linear polyester resin has repeating chain units of the formula: ##STR23## wherein each of R 1  and R 2  is a divalent aliphatic, alicyclic or aromatic radical containing 2 to 10 carbon atoms. 
     
     
       8. The process of claim 1 wherein the reaction is promoted with a catalyst. 
     
     
       9. The branched product of claim 1.